1. Field of the Invention
This invention pertains to a log splitting device having an outer driver sleeve which impacts against a telescopically housed inner driving shaft within the sleeve, which sleeve also serves as a guide channel to maintain the driver sleeve in common axial orientation with the impacted shaft as the sleeve is raised and lowered for impact.
2. Prior Art
Numerous wedge shaped devices have been developed as log splitting tools. The telescopic driver, sometimes referred to as a pipe-driver, is one such driver which is particularly convenient for a single user. It consists of an elongated driving shaft which has a wedge-shaped splitting tip mounted at its bottom end. This shaft is encased within an elongated driver sleeve which has a driver cap at the top for impacting the top end of the shaft. It is used by placing the splitting tip on the log, sliding the sleeve upward with respect to the shaft and slamming the sleeve downward to impact the cap of the sleeve on the top of the shaft. In this manner the momentum of the heavy sleeve is transferred to the shaft, forcing the wedge into the wood. The wood is split as the wedge is driven deeper into the wood.
The convenience of the driver arises from the fact that it is suitable for a single individual to handle. For example, use of a separate wedge and sledge hammer often requires two individuals in order to develop an efficient operation--one to hold the wedge while the other mans the hammer. The telescopic driver automatically maintains coaxial orientation between the driver and wedge and thereby eliminates the need for the second individual. Such prior art is illustrated in the following patents:
U.S. Pat. Nos. 4,350,192, 4,327,787, 4,101,088, and 3,519,234. PA1 U.S. Pat. Nos. 4,379,475, 4,405,005, 4,431,040, 3,050,095, and 4,280,540.
The -192 patent of Dent is typical of the previously described telescopic drivers. It includes a ring attached at the base of the shaft just above the wedge. A pair of handles are mounted midway at the sides of the sleeve to facilitate the repeated driving action as well as to enhance its portability. The device is usually carried and positioned by grasping the handle on the sleeve with one hand and by holding on to the ring or shaft with the other hand. This is necessary to keep the shaft from falling from its recessed position within the sleeve. Accordingly, such a tool requires the use of both hands.
In order to free one hand during carriage, some splitting tools have incorporated a retaining pin or other device for holding the shaft in the recessed position when the tool is not in use. Representative examples are illustrated in the following patents:
The -040 patent shows the use of a retaining pin for locking the shaft inside the sleeve when the tool is not being used.
The top of the shaft includes a flange or lip whose movement is blocked by the inserted pin. When the pin is removed, however, the shaft and flange are free to move within the sleeve. U.S. Pat. Nos. 4,379,475 and 4,405,005 illustrate the use of a cord or chain attached at respective ends to the sleeve and shaft to prevent the shaft from falling free of the sleeve.
Although prior art devices have provided a solution for carrying the splitting tool, a significant problem exists with respect to such devices during actual use. When the retaining pin is removed prior to use, the shaft is free to move. Obviously this is necessary if the device is to function properly with repeated impacts at the log to be split. However, when the wedge breaks through the log, the device will typically be moved to the next log. When lifted with the pin removed, the shaft simply remains at its ground position until the top of the shaft encounters a blocking flange at the base of the sleeve. It can then be raised by the sleeve to a new location. Alternatively, the user grasps the shaft with one hand and the sleeve with the other and moves both parts. Although this inconvenience can be tolerated for a short duration, repeated use would be greatly facilitated by a splitting tool specifically adapted for short movements between logs without the need to reach down and grasp the shaft and sleeve together.